Those over the age of 65 years represent the most rapidly growing group within the U.S. population. Approximately 25% of these individuals have significant hearing loss that interferes with everyday communication. Nonetheless, of those elderly who could benefit from the use of hearing aids, only about 20% actually seek them out and, of those who do purchase hearing aids, many are dissatisfied with them or discontinue using them. This project seeks to identify factors that underlie the successful use of hearing aids and to develop ways to improve the benefit received from hearing aids by the elderly. There are two primary components to the proposed project: (1) an examination of laboratory-based measures of cognitive function, especially attention, and their association with the speech-understanding performance of elderly hearing-aid wearers while they are wearing their hearing aids; and (2) a clinical investigation of the factors underlying individual differences in subjective benefit, satisfaction, and hearing aid usage among elderly hearing-aid wearers. For the laboratory studies, a series of experiments is proposed in each of three areas: (1) age- and hearing-loss-related differences in selective attention to different cues in multidimensional, speech-like sounds; (2) the role of cognitive factors, either lexical memory or selective attention, in the improvement of aided speech-recognition performance with training; and (3) the interaction of selective and divided attention with another key cognitive ability, working-memory capacity, and the contributions of these cognitive factors to the recognition of speech while other speech is in the background. The clinical study, on the other hand, seeks to determine how many dimensions of hearing-aid outcome are represented by measures of hearing-aid satisfaction, usage, and subjective benefit. Specifically, do these measures represent one, two or three separate aspects of hearing-aid outcome? In addition, variables underlying individual differences in each measure of outcome will be identified so that performance along each dimension can be both better understood and enhanced. [unreadable] [unreadable]